Good question—most city trash cans aren’t completely magic, but they’re designed to keep liquids contained instead of letting them seep onto the pavement. A common setup is a rigid outer bin with a sealed inner liner or heavy-duty bag. The inner container often has a closed, welded or one-piece bottom, so there are no seams for liquid to escape through. Some designs add a liquid-retention tray or sump at the bottom, which catches small amounts of leakage from torn bags or wet waste until the bin is serviced.
The lid matters too. Tight-fitting lids and overlapping covers help keep rain out and reduce the chance of liquid running down the sides. Gaskets or rubber seals around openings can also limit seepage. Materials are usually rust-resistant or coated, because a rusted-through base is exactly where leaks start.
Maintenance is the other half of the answer. Urban bins are emptied on a schedule, and many are washed or steam-cleaned to prevent buildup, odors, and corrosion. If a bag tears or the inner liner is damaged, crews replace it before it becomes a sidewalk problem. So the real protection comes from containment plus routine care: sealed liners, closed bottoms, retention trays, tight lids, and regular servicing working together.